GAIL (India) Limited

22placement of concrete, the surface shall be kept moist by spraying water at least for the period of 2hours and a thick coat of cement slurry shall be applied immediately before the placement of concrete.3.21.4 Inside the Form Works (Cleaning, Surface Preparation etc.)The interior of the form works, where the concrete is to be placed, shall be thoroughly washed by highpressure water jet or air jet to completely clean the entire volume from the dirts, grease/oil foreign anddeleterious materials etc. The reinforcements shall be completely cleaned and free from all sorts of dirtsgrease/oil, rust, foreign/deleterious materials etc. Before placement of concrete, the form works comingin contact with concrete, shall be coated highly with form oil or raw linseed oily material or providedwith any approved material to prevent adhesion of concrete to the form work, but utmost care shall betaken so that such oily material does not come in contact with the reinforcement.3.22 Placing and Compaction of ConcreteBefore placing the concrete, the Contractor shall ensure that:1. All mixing and placing equipment is thoroughly cleaned2. All concreting space is free from debris and rubbish3. All forms have been thoroughly wetted or oiled and firmly installed in line and plumb to theEngineer's approval.4. All reinforcement is cleaned of loose rust, scales and other injurious adherents and is firmlybound and correctly placed and has been so approved by the Engineer.5. All inserts, sleeves, foundation bolts and embedded parts have been correctly and firmlyinstalled to conform to the Engineer's drawings and have been carefully checked to complywith the drawings. Special care shall be taken to locate and check sleeves or inserts, whichmay not be symmetrically placed with respect to centre lines.The Contractor and Engineer shall separately inspect and check the above mentioned points and recordand sign the results in a register which shall be maintained by the Contractor in a approved form. Noconcrete shall be placed without the Engineer having inspected and approved in writing. Inspite ofensuring the above requirements, the Contractor shall fill pour cards furnishing the necessary details ofthe job, duly signed by the Engineer. This, however, will not absolve the Contractor from hisresponsibility to correctly execute the work. Pour cards shall contain the following information:Design Index- Date- Slump- Workability- Work test specimen- Type of finishing and admixtures used (if any)- Period of removal of shuttering/props/forms.a. The concrete pouring method shall be submitted to the Engineer for approval and shall alwaysbe such as to avoid any possibility of segregation of the components or shifting of thereinforcement.b. Special grout or mix shall be used for difficult and intricate locations as specified by theEngineer. During placing, the concrete shall be thoroughly worked around reinforcement,embedded parts and corners of the formwork.c. Greatest possible care shall be taken by the Contractor that reinforcement and embedded parts,particularly foundation bolts and sleeves, are not displaced during placement of concrete.While concreting mats and other such locations where top and bottom reinforcement areadopted, top reinforcement shall be thoroughly cleaned of all slurry and mortar sticking tothem at the time of concreting top layers.d. The concrete shall be placed and compacted before setting commences and should not besubsequently disturbed. No water shall be mixed with the concrete after it has left the mixer.Method of placing should be such as to preclude segregation. Approved mechanical vibrator